In the fabrication of many electrical products it is frequently necessary to establish a plurality of upstanding terminal pins on a substrate. For example, on printed circuitboards, it is necessary to establish terminal points to which external wiring can be secured. Various types of apparatus are known which operate from a continuous supply strip to intermittently feed, sever and drive terminal pins into a workpiece. However, all such known prior art apparatus and terminal pins inserted thereby suffer from the disadvantage that the terminal pins formed and inserted in the substrate terminate in end portions which have the same planar cross-sectional area as the supply stock from which the terminal pins were formed.
Such blunt end portions of the terminal pins formed and inserted by apparatus of the prior art are particularly undesirable especially in the environment in which a wire wrap operation is to be applied for electrically connecting an external wire to the terminal pin. In fact, many OEM manufacturers who have to employ wire wrapping techniques to electrically connect to printed circuitboards will refuse to accept terminal pins in such boards where the terminals terminate in blunt end portions of the same planar cross-section as the pin itself. Apparently, the blunt nature of the terminal pins makes it difficult to center the wire wrapping operation which is to take place for establishing electrical connection to the printed circuits.
Another problem associated with the prior art apparatus for forming and inserting terminal pins in printed circuitboards, and somewhat related to the fact that the end portions of the inserted pins are of the same planar cross-section as the remainder of the pins, is the fact that during the shearing operation necessary to form the individual pins, an undesirable burr remains on the sheared pins. The thicker the cross-section of the supply stock, the more difficult it is to effect a shearing operation and the more pronounced is the undesirable burr which results.